1. Field
The invention is in the field of containment devices and systems for wash fluid, generally wash water, used in washing objects such as vehicles and equipment where the wash water after washing may have contaminants or a high solids content such as when washing dirt, oils, and mud from a vehicle.
2. State of the Art
With increased concern for the environment, washing items, particularly large items such as vehicles, can raise a problem of containment and disposal of wash fluid, usually water The wash fluid can contain various contaminants ranging from soap, detergent, and wax which may be added to the fluid prior to washing; gasoline, oil, and grease that may be washed from a vehicle or other piece of equipment; to various other contaminants and solids that build up on a vehicle or other equipment during use and are washed off with the wash fluid,
Permanent wash sites have washing pads which collect the used wash fluid and direct it into a drain or collect it in a below grade open tank like structure or holding basin from which it can be pumped for disposal. Usually a grate is placed over the holding tank structure to form a surface on which the vehicle or other equipment to be washed may be located for washing. The wash fluid flows from the object being washed, through the grate, and into the holding tank. With open holding tanks, wastewater builds up with inevitable formation of bacteria which create health hazards and odor. Holding tanks for hazardous waste may also require construction of secondary containment systems and alarm systems in many locations, Also, such permanent sites now may require special permitting since they contain what may be considered as hazardous materials. A further problem is that during washing of an item it may be difficult for an operator to keep the fluid jet used for washing from impacting the fluid in the basin. When it does, dirty fluid, including oil floating in the fluidbasin, is splashed on the object being cleaned and on the operator. This not only requires that the object to be cleaned again, but it also creates operator hazards because of the chemical and biological agents contained in the basin.
To clean a permanent holding tank, the access grate or manway must be removed and the waste extracted by draining, vacuuming, shoveling, or pumping. Such cleaning is difficult, time consuming, and renders the washing pad unusable during such cleaning.
A number of portable wash water containment devices have been proposed. Most of these take the form of an open top tank or pan over which a grate is placed to form a surface that supports the vehicle or other item to be washed. The wash water then flows from the item being washed, through the grate, and into the tank, see, for example, U.S. Pat. No. 6,021,792. A special waffle collecting and drainage pan may be used in the tank as in U.S. Pat. No, 5,738,139. In some cases, the equipment is merely placed in the tank with no supporting surface grate and the tank may merely be a waterproof membrane extending over an area bounded by raised sides, the membrane forming the water holding tank, see U.S. Pat. Nos. 5,547,312 and 5,597,001. The fluid may be drained from the tank in various ways such as through a drain or into a sump from which it can be pumped. As indicated, with vehicle washing, significant amounts of solids may be washed from the vehicle and settle in the tank. These solids build up and can easily plug any drain provided or fill up any sump provided. To remove such solids or other debris that may collect, it is necessary to remove any grate or other support surface provided to allow access to the tank. This is difficult and time consuming and renders the washing pad unusable during the cleaning process. If no surface above the holding tank is provided, the equipment sits in the holding tank with the collected wash fluid. The holding tank still has to be cleaned, and probably more often than when a surface above the tank is provided, so that the item to be washed does not sit in a puddle of mud and fluid.
Another problem with portable systems is that the collecting tanks are relatively shallow. With relatively shallow tanks, a slight variation in elevation, such as when placed on an uneven surface, can cause one end of the tank to be dry while another overflows, defeating the purpose of using the tank. If the deep end does not contain a suitable drain, it is virtually impossible to remove fluid from the tank. Further, the capacity of the tank is seriously reduced in such situations which then requires more frequent cleanings.
According to the invention, a wash fluid containment system includes an elevated, fluid impervious surface upon which an item is positioned to be washed. The surface is configured to cause the fluid to flow to an edge of the surface to prevent buildup of fluid, solids, or debris on the surface. For this purpose, the surface may include a flange along edges other than those to which the fluid flows and the surface may be sloped slightly toward the desired edge. It is presently preferred to configure the surface to cause the fluid, solids, and debris to flow to a single side of the surface, but it could be configured to flow to more than one side or to all sides of the surface. A collecting trough is located along the edge or edges of the surface to which the fluid flows and in fluid flow communication therewith so that fluid flows from the surface into the collecting trough or throughs where such fluid is received and confined. Washing fluids may be drained from or pumped from the trough for disposal or treatment. If treated, the washing fluids may be recirculated. In a preferred embodiment of the system, a trough is deep enough to hold a sump pump or an outlet is provided in the trough for connection to the inlet of a pump, such as an in-line pump. Fluid is pumped from the trough to evacuate the fluid from the trough and to dewater any solids that have settled in the trough. Weirs and/or oil coalescing material may be placed in the trough intermediate its length to help settle solids from the wash fluid in the trough.
In a presently preferred embodiment of the elevated surface, the surface is formed to have a plurality of supporting rails which support a vehicle or other piece of equipment thereon and a plurality of fluid flow channels located between the rails so that wash fluid, solids, and debris from the vehicle or other item being washed flow into the channels. The channels are open at one end along one side of the device and may be sloped toward the open end so that the wash fluid will flow through the channels and out the open ends of the channels into the collecting trough positioned along the side of the device in flow communication with the plurality of channels, Since the collecting trough is located along the side of the device it is easily accessible for cleaning and solids removal during use of the device. The flow channels can be easily cleaned without disassembly (such as removal of a covering grate) of the device and such cleaning can take place during use of the device or as part of the use of the device. No disassembly of the device is necessary for cleaning or solids and debris removal.
The device preferably is constructed in modules which are portable and can be used singly for small vehicles and other equipment or can be combined with additional modules to create a larger device to accommodate large trucks and other large equipment. Modules of eight feet by eight, ten, twelve, or fourteen feet have been found satisfactory, although other sizes can be used. Such modules can be secured side-by-side or end-to-end to create larger washing surfaces. Walls and, if desired, a roof can be attached to the collecting devices to partially or fully enclose them to help ensure that all wash fluid stays on the device rather than being sprayed or splashed off the device. When enclosed, lighting and ventilation can also be provided.
Portable devices of the invention are preferably structurally rigid and provided with fork lift slots and lift points that allow rapid deployment on unimproved dirt surfaces. Such portable devices can be easily leveled as with shims and be ready to use generally in less than a day. Because they are portable, most localities consider them to be personal property which eliminates any permitting and inspection requirements which would be present if permanent washing facilities were being constructed.
A method of containing wash fluid according to the invention includes the steps of positioning an item to be washed on a substantially fluid impervious elevated surface which is configured to direct wash fluid used to wash the item, along with any solids and debris washed from the item, to one or more sides of the surface where it flows from the surface, positioning a collecting trough along the one or more sides of the surface in flow communication therewith to collect the fluid, along with any solids and debris that may be present flowing from the surface, and removing the wash fluid, and any solids and debris, from the collecting trough.